Nuclear factor erythroid-2 related factor-2 (Nrf2) is a redox-sensitive transcription factor that regulates genes encoding phase II detoxification enzymes and antioxidant proteins. Following oxidative or electrophilic stress, Nrf2 is liberated from its inhibitor, Keap1, allowing nuclear translocation, and the transcriptional induction of its target genes. Nrf2 plays a central role in the regulation of antioxidant response element (ARE)-mediated gene expression. Our lab has reported that genetic alterations in Keap1 are a frequent occurrence in non-small-cell lung cancer (NSCLC) that leads to increased Nrf2 expression and constitutive activation of Nrf2-mediated gene expression. Constitutive activation of Nrf2 due to the loss of Keap1 function in lung tumors contributes to the survival and growth of cancer cells as well as confers chemoresistance in NSCLC. The identification of a well-defined Nrf2 regulatory program is a critical step in understanding the dysregulation of Nrf2 activity in cancer cells, which promotes both tumorigenesis and therapeutic resistance leading to novel intervention strategies. Our preliminary data from microarray analysis demonstrate that constitutive activation of Nrf2 in lung cancer cells up-regulates a large number of genes with overarching implications in tumorigenesis and chemoresistance. Recent studies provide strong evidence that DNA binding co- factors can modulate Nrf2-driven transcriptional activity and target gene expression. This proposal outlines a systems biology approach for the identification of binding partners in the Nrf2 transcriptional activation complex that are responsible for the differential regulation of Nrf2 target gene expression in lung cancer. These studies will reveal the role of Nrf2 binding partners in ARE- directed gene expression. By understanding the regulation of Nrf2-mediated transcription, we will discover the mechanism responsible for the altered gene expression in lung cancer. This proposal aims to identify novel therapeutic targets involved in the regulation of Nrf2-mediated gene expression and gain insight into the role of Nrf2-mediated gene expression in carcinogenesis and chemotherapeutic resistance.